Rock drilling mechanism



y 12 1964 3. A. LARCEN 3,132,703

ROCK DRILLING MECHANISM File M y 1 1956 8 Sheets-Sheet 1 g ZZZJ I00 49Fig.2

lNVENOR I 57 B a. M 66 ATTORNEY May 12, 1964 J. A. LARCEN 3,132,703

ROCK DRILLING MECHANISM Filed May 15, 1956 8 Shee -Sheet 2 v INYZZTORIIf W ATTORNEY May 12, 1964 J. A. LARCEN ROCK DRILLING MECHANISM 8Sheets-Sheet 3 Filed May 15, 1956 y m E m F 3 5 w in 6 I 8 q. a I L lIM\|\ w W H I I ll VIIIWTIII rl May 12, 1964 .1. A. LARCEN 3,132,703

ROCK DRILLING MECHANISM Filed ma 15, 1956 8 Sheets-Sheet '4 M /24 7 /22Fig. 15 64 my 65 Fig. /4 f/2/ 6 //0 65 g I J 77 7 //O [2O III 7 2 May12, 1964 J. A. LARCEN 3,132,703

ROCK DRILLING MECHANISM Filed May 15, 1956 a Sheets-Sheei 5 F /5' Fig/7QQATTQRNEY INVENTO fizz? May 12, 1964 Filed May 15, 1956 J. A. LARCENROCK DRILLING MECHANISM 8 Sheets-Sheet 7 INVENTOR l X; aw

v rATTORNEY y 2, 1964 J. A. LARCEN 3,132,703

ROCK DRILLING MECHANISM Filed May 15, 1956 8 Sheets-Sheet 8 Fig. 28

Fig. 25

2/6 2/9 W H 232 250 2. 2 233 253 I 44256 Fig. 24

ATTORNEY United States Patent 3,132,703, ROCK DRILLING MECHANISM JanAugust Larcn, Elrtorp, Sweden, assignor to Atlas Copco Alttiehoiag,Nacha, Sweden, in corporation of Sweden Filed 15, 1956, Ser. No. 584,9709 Claims. (Cl. 173-62) This invention is a continuation-in-part of JanAugust Larcns co-pending application Ser. No. 387,847, filed October 23,1953, now Patent No. 3,085,638, and relates back thereto for all commonsubject matter.

The present invention relates to rock drilling mechanisms comprising adrill steel actuating motor arranged for cooperation with a pneumaticfeeding device such as a feed leg, a stopper or drifter or the likeserving to move the drill motor towards the rock face to be drilled. Oneobject of the invention is to reduce the time needed by the operator formaneuvering rock drilling mechanisms of this type. A further object ofthe invention is to provide concentrated control means for the operationof a rock drilling mechanism comprising a drill and a feeding device. Afurther object of the invention is to provide a. rock drilling mechanismwhich is quick and simple in operation and cheap in manufacture. A stillfurther object of the invention is to provide a rock drilling mechanismin which the means for holding and controlling the rock drillingmechanism and for controlling a feeding device for the same areconcentrated to the rear end face of the back head of the drill. A stillfurther object of the invention is to provide a rock drilling mechanismin which the control means of the drill and feeding device are disposedin such a way in the back head that the drill may be moved very close toa wall or a roof in a working place where drilling is performed and inwhich the operating means of the drill and feeding device are easilyaccessible even in such drilling positions. Other features of theinvention will be apparent from the following description of someembodiments of the invention which, however, should only be consideredas examples and which by no means limit the scope of the invention asset forth in the claims.

FIG. 1 is a side view partly in section of a rock drill and a feed legforming a drilling mechanism according to the invention. FIG. 2 is ahorizontal view of the rock drill and a portion of the feed legaccording to FIG. 1. FIGS. 3 and 4 illustrate on a larger scale partsforming a member for hingedly connecting the feed leg to the rock drill.FIG. 5 is a detail view also on a larger scale illustrating a handle andassociated valve mechanism on the feed leg. FIG. 6 is a detail sectionalso on a larger scale of the foot end portion of the feed leg. FIG. 7is a side view and partial section of a rock drill forming a part of thedrilling mechanism according to the invention. FIGS. 8 and 9 arediagrammatic sections of the back head of the rock drill according toFIG. 7 illustrating a main valve and pressure reduction device andpassages for supplying pressure fluid for feeding purposes. FIGS. 10 and11 are similar diagrammatic sections of the back head illustrating themain valve and associated means and passages for supplying flushingwater to a hollow drill steel. FIGS. 12 and 13 are similar diagrammaticsections of the back head illustrating means for venting the feed legthrough the main valve. FIGS. 14 and 15 are similar diagrammaticsections of the back head illustrating the main valve and passages forcompressed air flushing of the drill hole. FIG. 16 is a side view andpartial section of a modification of the feed leg illustrated in FIGS.1-6. FIG. 17 is a further View of a portion of the feed leg of FIG. 16.FIG. 18 is a diagrammatic section of the back head of a drill with amodified valve device for use in connection with the feed leg of FIGS.16 and 17. FIGS. 19 and 20 are detail sections of the valve deviceaccording to FIG. 18. FIG. 21 is a side view partly in section of adrilling mechanism according to a further embodiment of the invention.FIG. 22 is a rear end view of the back head of the drillling mechanismaccording to FIG. 21. FIG. 23 is a section on line XXIII-XXIII in FIG.21. FIGS. 24 and 25 are sections on line XXIV-)QHV and XXV-. XXV,respectively, in FIG. 21. FIG. 26 is a section on line XXVI-XXVI in FIG.23. FIG. 27 is a partial plan view of the back head and the drillaccording to FIG. 21 and FIG. 28 is a'section on line XXVIII- XXVIII inFIG. 26.

The drilling mechanism illustrated in FIGS. 1-20 in and for movement ofthe motor towards a rock face to be drilled.

The drill steel actuating motor may, of course, be of any suitable typeand is here illustrated as a hammer rock drill having a casing 1 and aback head 2 and the feeding device is illustrated as a feed legcomprising a cylinder 3 in which a piston'4 and a piston rod 5 aremovable under the action of compressed air and which is hingedlyconnected to the casing 1. The cylinder 3 is provided with a head 6 inwhich a body 7 is secured, said head and body forming together means forconnecting the cylinder 3 to the drill 1. The body 7 for this purposehas formed thereon a trunnion 8 which is journalled in a bearing 9formed by a lug 10 on the underside of the casing 1 of the drill asshown in FIG. 7. The trunnion 8 is provided with bearing surfaces 11separated by annular grooves 12 and 13, respectively, and provided withsealing rings 14, 15, 16 which together with the bearing surface 9 forma sealing between the grooves 12 and 13 as well as between the groovesand the atmosphere. A nut 17 is secured on screw threads 18 at one endof the trunnion 8 and forces a spring 19 with a friction washer 20against one side of the lug 10, whereas a conical surface 21 on thetrunnion 8 bears against a conical surface at the opposite side of thelug lil which is indicated in chain dotted lines in FIG. 3. A passage 22communicates with the groove 12 and an opening 23 in the body 7 and apassage 24 forms a communication between the groove 13 and an opening 25in thebody 7, as obvious from FIG. 3. The openings 23 and 25 registerwith openings of passages 26 and 27,

connected through a pipe 28, see FIG. 4, with a bracket 29 forming adistributing valve housing and the base of a handle 30 fixed on thecylinder 3 by means of a screw bolt 31. The pipe 28 communicates througha passage 32 with a' space 33 in a distributing or shiftable valvedevice provided in the bracket 29 of the handle 30. The passage 27 alsocommunicates with the interior of the cylinder 3 through a passage 36which is formed as a branch of passage 27 as shown in FIG. 4. Theinterior of the cylinder 3 furthermore communicateswith a passage 37leading to a space 38 in the head 6 which by means of a spring actuatedball valve 39 is separated from a passage 40 in the head 6 leading tothe atmosphere. A spindle carrying a push button 41 is provided in thehead 6 for opening the valve 39 when the operator desires to vent thecylinder 3 to the atmosphere through the passage 37, space 38 andpassage 40. Such venting is sometimes desirable when the drill steelmeets cracks in the rock or for other purposes.

The bracket 29 has a transverse bore 42 accommodating a shiftable slidevalve 43 provided with lands 44 and 45 separated by an annular reducedportion 46 forming the space 33. A passage 47 opening in the bore 42com- 3 municates through a pipe 45 with a lower head 49 on the cylinder3. A passage 50 in the head 49 leads from the pipe 48 to a Workingchamber 51 in the cylinder 3 formed between the piston 4, the piston rod5, the cylinder 3 and the lower head 49. The chamber 51 constitutes aworking chamber for pressure fluid in the feed leg for producingcontraction of the feed leg. A chamber 52, FIG. 1, is formed in thecylinder 3 between the piston 4 and the head 6 and forms the Workingchamber for pressure fluid acting to expand the feed leg.

As soon as the drill is connected to a supply of pressure fluid, such ascompressed air, pressure fluid flows through passages in the drill whichwill be described hereinbelow to the grove 12 in the trunnion 8 andfurther through the passage 22, the port 23, the passage 26 in the head6, through the pipe 28 and the passage 32 to the space 33 in the bracket29. The handle 30 is provided with a trigger 53 which when pressedtowards the handle moves a pin 54 which displaces the valve 43 againstthe pressure of a spring 55 so that the space 33 between the lands 45and 44 provides a communication between the passage 32 and the passage47 thereby conveying pressure fluid to the pipe 48, the passage 50 andthe contraction chamber 51 of the feed leg. The displacement of thevalve 43 to the right in FIG. by means of the trigger 53 causes land 44to uncover the opening of passage 35 thereby opening a vent passage fromthe working chamber 52 through the passage 36, the passage 27, the pipe34, the passage 35 in the bracket 29 and a passage 56 to the atmosphere.The pressure fluid acting in the chamber 51 then causes contraction ofthe feed leg.

.The piston rod 5 is provided with a foot portion 57 adapted to rest onthe ground or any suitable structure or wall in the working place.

The drill steel actuating motor as mentioned hereinabove consists of acasing 1 and a back head 2. A suitable steel retainer 58 for a hollowdrill steel 59 is provided in conventional manner at the front end ofthecasing 1. A handle 60 is provided on the back head 2 in conventionalmanner. The casing 1 contains a reciprocable hammer piston 61 which uponreciprocation in a manner known per se delivers blows to the shank ofthe hollow drill steel 59. A flushing medium tube 62 extends through thehammer piston 61 into a duct 63 for flushing medium in the drill steel59 in a manner which is also very conventional in connection with rockdrills. The back head 2 contains a conical valve member 64 which may beoperated by means of a handle 65. Compressed air is supplied to thedrill through a hose 66 and a tube 67 fitted in the back head 2 endwiseof the valve member 64. The valve member 64 is bored as indicated at 68and this bore communicates with a port 69 in the valve member whichwithin a certain angle of displacement of the handle 65 communicatesthrough a passage 70 in the back head 2 with valve chambers 71 and 72.The valve chambers may be brought into communication with workingchambers 73 and 74 behind and in front of the piston 61 through passages75 and 76, respectively. A flapper valve 77 is provided in the drill fordistribution of compressed air to the chambers 73 and 74. 73 indicates agroove in the cylinder wall communicating with exhaust ports 79 of thedrill.

A passage 80, FIG. 13, in the back head 2 is in constant communicationwith the compressed air supply pipe 67 and comunicates through a passage81 in the casing 1 with the grove 12 in the trunnion 8, FIG. 3, asdescribed hereinabove, and supplies compressed air of line pres sure tothe space 33 in the bracket 29, FIG. 5.

The valve member 64 has a further bore 82, FIGS. 8, 9 which through apassage 83 and a groove 84 in the valve member 64 in certain angularpositions of the valve member 64 may be brought into communication witha passage 85 leading to a pressure reduction device which consists of avalve member 87 rotatable in a plug 86 in the back head 2 by means of ahandle 88. The valve mem ber 37 has vent passage 89, FIG. 8, leading tothe atmosphere and communicating with a groove 90 in the valve member87. Another groove 91 in the valve member 87 communicates through a bore92 with the passage 85. Both grooves 90 and 91 register with an opening98 in the plug 36. The grooves 90 and 91 are of such relative dimensionsand shape and varying width as to control the distribution of air ventedto the passage 89 and supplied to a passage 93 leading to a passage 94in the casing 1 and the groove 13 on the trunnion 8 and further throughthe passages 24, 27 and 36 to the working chamber 52 of the feed leg.Consequently, by suitable adjustment of the handle 88 the pressure inthe Working chamber 52 of the feed leg may be adjusted at the will ofthe operator. The back head 2 has a passage 95 which through a groove 97in the plug 86 connects the passage 93 through a groove 96 and the port70, FIG. 12, with the atmosphere through.

the working chamber and exhaust 78 of the drill for venting the workingchamber 52 of the feed leg in certain angular positions of the handle 65and the valve member 64.

Flushing water is supplied to the drill through a flushing water tube100 connected to a tube 101 fitted in the back head 2 and communicatingthrough a passage 102,

FIG. 11, with a valve chamber 103 containing a spring.

actuated ball valve 104 operated to open position by a pin 105 which isin contact with a cam surface 106 on the valve member 64 due to thepressure of the flushing water and a spring 107 acting on the ball valve104. open position the ball valve 104 provides communication between thepassage 102 and the chamber 103 to a pas sage 108 communicating with theflushing medium tube 62. Within certain angular positions of the handle65 the cam 106 operates the flushing water valve 104 to provide more orless flushing water to the flushing medium tube 62. The valve member 64is provided with a passage 110, FIGS. 9, l4 and 15, communicating withthe bore 82 and in certain positions of the valve member 64 with apassage 111 in the back head 2 which passage also medium tube 62 and theduct 63 of the drill steel at full.

line pressure and simultaneously the working chamber 52 of the feed legis vented to the atmosphere through the control valve 64 and exhaustports of the drill, FIG. 12. When the handle 65 is moved from theposition 7 past the position 121 the vent passage 95 for the chamber 52is closed. After further movement of the handle 65 to the position 122air is admitted to the working chamber 52 of the feed leg through thegroove 84 and passage 85, FIG. 8, so that feeding of the drill towardsthe rock face is initiated. After further turning of the valve handle 65to the position 123 flushing water also starts to flow to the flushingmedium tube 62 due to actuation of the spindle 105 by the high portionsof the cam surface 106 while the drill is fed towards the rock. In theposition 124 the supply of feeding air and flushing water increases andthrough port 69 air is also admitted to the drill motor, which starts tooperate slowly. This is the position Where collaring begins. feedingpressure and water supply is obtained and the drill motor operates withincreased speed. The handle 65 is then turned to the position 126 wherethe drill operates 'at full speed with full feeding pressure and full Inthe position 125 full which controls the relation of the areas of thegrooves and 91 uncovered by the port 98, FIG. 8.

When a hole has been driiled the operator returns the the feed leg byair supplied to the working chamber 51 so that he can bring the footportion 57 into a new advanced position. Upon turning of the handle 65again to the position 126 the drilling mechanism continues the drillingand feeding operation in the same manner and with the same setting ofthe feed pressure and flushing water supply as before. A spring pressedplunger 139, FIG. 9, cooperating with notches 131 on the valve member 64retains the valve member in various positions from the position to 126Without the operator having to keep his hand on the handle 65.

The modification of the invention illustrated in FIGS. 16-20 consists ofa feed leg comprising a cylinder built up by two tubular members 132 and133 accommodating a piston 134 and a piston rod 135. The members 132 and133 are fitted in a head 136, similar to the head 6, in which the body 7fits. The members 132 and 133 are also fitted to a lower head 137through which the piston rod 135 extends and carries a foot portion 57.The head 136 has a passage 138 communcating through the body 7 with thepassage 81 of the drill. The passage 138 communicates with a space 13?between the tubular members 132 and 133 which through openings 140 inthe tubular member 132 communicates with a working chamber 141 on theunder side of the piston 134. Compressed air admitted to the chamber 141produces contraction of the feed leg when a working chamber 142 on topof the piston 134 is vented to the atmosphere. The head 136 is providedwith a vent passage 37, FIG. 17, leading from the chamber 142 to a space33 in the same way as in the head 6. The space 33 is by means of aspring actuated ball valve 39 separated from a passage 40 leading to theat mosphere. A spindle carrying a push button 41 is provided in the head136 for opening the valve 39 when the operator desires to vent thechamber 142 to the vatmosphere. The head 136 is also provided with apassage 143 communicating with the chamber 142 and through the body 7with the passage 94 in the drill.

The tubular member 133 carries a handle 144 corresponding to the handle31 but the valve mechanism in the handle 39 has been placed on thedrill. For this purpose a conical shiftable distributing valve member145, FIGS. 1820, is provided in valve housing means formed in the backhead 2, this valve member being rotatable by means of a handle 146. Apassage 147 corresponding to passage 80 in FIG. 13 communicates with aspace 148 at the big end of the conical valve member 145. The valvemember has two grooves 149 and 150, FIGS. 18 and 19, the groove 14%providing communication between the passage 147 and the working chamber141 in the position of the valve member 145 illustrated in FIG. 19. Thisis the position for contraction of the feed leg. A 90 turn of the valvemember 145 causes the groove 150 to bring the passage 81 intocommunication with a vent pas sage 151 to the atmosphere for venting theworking chamber 141. A groove 152, FIG. 20, in the valve member 145provides communication between the passages 93 and 94 for supplyingcompressed air of suitable pressure to the working chamber 142 forexpansion of the feed leg. A further groove 153 serves for venting ofthechamber 142 through the passage 151 after a 90 turn of the valvemember 145 from the position in FIG. 20, i.e. to the position in FIG.19. It is obvious that the feed leg of FIGS. 16-20 operates in the sameWay as the feed leg illustrated in FIGS. 1-6 only that the valve devicein the handle 39 has been moved to the drill and the externally disposedpipes 28, 34 and 48 have been dispensed with.

The drilling mechanism illustrated in FIGS. 21-28 consists of a drillwhich is arranged for cooperation with an expansible andcontractiblefeed leg whichmay be hingedly connected to the drill forsupporting the drill and for movement of the drill towards a rock faceto be drilled and of a type illustrated in FIGS. 3, 16 and 17.

The drill illustrated in FIGS. 21-28 is a hammer rock drill having acasing 291 and a back head 202. The body 7, FIG. 3, of the feedingdevice may be journalled with the trunnion 8 in a bearing 299 formed bya lug 210 on the underside of the casing 291 of the drill, FIG. 21. Thecasing 2111 forms a Working cylinder 203 for compressed air in which ahammer piston 204 is reciprocable. A flushing medium tube 205 extendsthrough the drill to the drill steel 266 which is hollow in conventionalmanner. A second tube 207 encloses the tube 205 and extends from theback head through the drill to the chuck chamber as is also well knownin the art. The casing 2111 and the back head 202 are held together bytwo sidebolts 2138 extending through the back head 202 in conventionalmanner. The back head is provided with a transversely extending handle211' which is off-set to one side of a plane 212 through the centre ofthe side bolts 268. A cylindrical main valve member 213 is rotatable ina cylindrical bore in a sleeve 214 fixed by means of a screw threadedbushing 215 and arranged with the bore axis parallel with the axis ofthe working cylinder 263 and off-set to the opposite side of the plane212 to the handle 211. The valve member 213 is provided with anoperating lever 216 which may be manipulated by the fingers of a handholding the handle 211. Compressed air is supplied to the back headthrough a pipe 217, FIG. 22. The valve member 213 is arranged forcontrol of the supply of compressed air to the drill motor and to thefeeding device and for the control of flushing medium supply through theflushing tube 205 and of air through the tube 2117, as will be describedin detail below.

A cylindrical auxiliary valve member 218, FIG. 26, is rotatable in acylindrical bore in a bushing 219 which is secured in the back head 202by means of ,a screw threaded bushing 2241 with a bore axis parallelwith and off-set with regard to the plane 212 to the same side of saidplane as the valve member 213. The auxiliary valve member 218 isprovided with a manipulating lever 221. The valve member 218 is arrangedfor control of the pressure of the compressed air in the feeding device,as will be described in detail hereinbelow.

A second auxiliary or distributing valve member 222 is movable in asleeve 223 fitted in the back head 202 and kept in place by the handle211. The valve member 222 is an air vent valve for venting the feedingdevice as.

will be described hereinbelow. A double arm lever 224 is swingable on apivot 225 in the handle 211 for operating the valve member 222 by meansof a push rod 226, FIGS. 26 and 27.

The backhead 2112 also contains a flushing water control valve 227, FIG.23, which is formed on one end of a push rod 228 actuated by the mainvalve member 213 as will be. described hereinbelow. The valve member 227cooperates with a seat 229 which is kept in place in the back head by ascrew threaded bushing 230. Flushing water is supplied to the back headthrough a water pipe 231.

The rock drill according to FIGS. 21-28 cooperates in the followingmanner with the telescopic feeding device illustrated in FIGS. 3, 16 and17. Compressed air supplied to the back head through the pipe 217 entersthe backhead at 232, FIGS. 24 and 25, and a reduced air stream isconducted through a bore 233, FIG. 25, to an annular space 234- andopenings 235 in a member 236 to a passage 237 between the flushing watertube 265 and the tube 2117 to the chuck chamber of the drill causing airto flow through the chuck chamber for lubricating the chuck and adjacentparts and for blowing the drill hole with air. An air duct 238,.FIGS. 24and 26 leads from the space 232 to a groove 239, FIG. 26, in the sleeve223. An annular groove 240 in the sleeve 223 is connected through apassage 241 through the casing 201 to the bore 2119 in which itcommunicates with the groove 12 and the duct 22, FIG. 3, and furthermorethrough the passage 138, FIG. 16, and the space 132 through openings 140with the lower chamber 141 of the feed leg. Compressed air admitted tothe chamber 141 contracts the feed leg when the space 142 is vented tothe atmosphere. A duct 242 in the back head and the casing 1 whichcommunicates with an annular groove 243 in the sleeve 223, FIG. 26,opens in the bore 289 and communicates with the groove 13, FIG. 3, andthe duct 24 leading to the space 142, FIG. 16. Compressed air ofsuitable pressure supplied through the duct 242 causes expansion of thefeed leg. The sleeve 223 has a further annular groove 244 which througha passage 245, FIG. 26, communicates with an annular space 246 in thesleeve 219. The auxiliary valve member 218 has two grooves 247 and 248carried out in similar way as the grooves 90 and 91 of the valve member87, FIG. 8, with oppositely decreasing area. A bore 250 in the valvemember 218, FIG. 26, communicates with a bore 251 in the back head 202and a duct 252 opening in a port 253 in the main valve sleeve 214, FIG.25, and may be connected through a groove 254 in the main valve memberto ports 255 or 256 in the sleeve 214 which are always in communicationwith the live air supply space 232. As soon as the main valve member 213is moved to positions in which the groove 254 registers with the port253 live air is supplied to the bore 250 of the auxiliary valve member218. From the bore 259 the air is conducted to a bore 260 and the groove247 and through a bore 259 to the space 246. More or less of the airadmitted to the space 246 is vented to the atmosphere through the groove248, a port 268, FIG. 26, a bore 257 and a vent passage 258 in the valvemember 218 so that the air pressure from the passage 255 to the space246 is reduced more or less thereby reducing the power of the feedingdevice according to the adjustment or the valve 218. The sleeve 223,FIG. 26, is provided with two annular grooves 261, 262 which communicatewith the atmosphere through passages 263, 264 and with the bore of thesleeve through ports 265, 266. In the position of the valve 222illustrated in FIG. 26 air is vented from the underside of the piston134, FIG. 16, through passage 241, groove 240, a space 292, port 266 andpassage 264, and when the valve 222 is depressed against a spring 267the vent passage 264 is closed and air is instead vented through thepassages 242 and 263 from the upper side of the piston 134 in FIG. 16.

The main valve member 213 has a peripheral groove 271) which may producecommunication between the supply chamber 232 through the port 255, thegroove 270, and a port 272 to a passage 271 leading to the space 234 andopening 235 and serving to supply live air to the chuck chamber and forfull pressure air blowing through the flushing medium duct of the drillsteel. The main valve' member 213 has a large port 273 which may bebrought to register with the port 255 in the sleeve 214 in order tosupply compressed air to a bore 274 in the main valve and a passage 275leading to the drill motor. Operation of the device described inconnection with FIGS. 2l-28 hereinabove is substantially the same as theoperation of the device described in connection with FIGS. 7, 8, 9, 16and 17.

"It will be appreciated, however, that all controls for the drillingmechanism illustrated in FIGS. 21-28 and 3, 16, 17 are disposed withinthe confines of the rear end face of the backhead 202. The provision ofcylindrical valve members 213 and 218 makes possible a design of a backhead in which valve adjustments are sufficiently easy to be performedwith the aid of short levers provided on the valve members which may bemanipulated with the fingers of a hand holding the handle 211. It isalso obvious that the valve operating levers do not project out side theconfines of the back head so that the drill may.

be moved very close to a rock wall or roof with the upper, lower or lefthand side of the drill as is often desirable.

The operating scheme of the drilling mechanism according to FIGS. 3, 16,17 and 2l-28 is easily understood with reference to FIG. 22. figures alllevers are illustrated in stop position. In said position no compressedair is supplied to the drill motor and air is vented from both cylinderchambers of the feed leg. No water is supplied to the flushing duct-sbut a reduced air stream flows to the chuck cham-v ber through the smallopening of passage, 233. Turning,

of the lever 216 to the position 280 causes air to be supplied to theflushing duct of the drill steel from the space 232 through port 255,groove 270, port 272, passage 271, FIGS. 24 and 25, space 234, FIG. 21,ports 235 and passage 23-7 to the chuck chamber of the drill in whichthe piston 224 is lifted from the shank of the drill steel 296. When thelever 216 is moved to the full line position in FIG. 22 flushing airsupply over the groove 278, FIG. 24, is interrupted. Upon movement ofthe lever 216 to the position 282 compressed air is first admitted tothe feeding device from the space 232 through port 255, groove 254, port253, passage 252, bore 251, bore 255, bore 260, groove 247, port 259,space 246, passage 245, groove 244, space 291, groove 243, passage 242,groove 13, FIG. 3, passage 24, port 25, passage 143 and space 142 on topof the piston 134. Since the underside of the piston 134 is vented theair pressure in the chamber 142 causes extension of the teed leg. Thepressure of the compressed air in the chamber 142 is con trolled by thehandle 221. In the position of FIG. 22 all air supplied to the space246, FIG. 26, is vented to the atmosphere through port 268 and bores 257and 258,

but as soon as the lever 221 is turned in the direction towards theposition 281 the amount of air escaping from the space 246 is reduced.This is due to the tact that when the lever 221 is turned clockwise fromthe full line position of FIG. 22 towards the position 281 the port terwas supplied from the pipe 231 through a space 294,

a duct 295, a space 296, FIG. 23, ports 297, FIG. 21, through theinterior of the flushing tube 205 to a flushing duct 298 in the drillsteel 206. Further movement of the lever 216 to the position 283 causescompressed air to be supplied from the space 232 through port 255, FIG.24, port 273, bore 274, and passage 275 to the distributing valve andworking chambers of the drill motor. movement of the lever 216 to theposition 284, FIG. 22, brings the port 273 to register exactly with port255, FIG. 24, so that full air supply is obtained to the drill motor.When it is desired to momentarily contract the feed leg or to reduce thefeed pressure the lever 224 may be pressed. Venting of the space 141 onthe underside of the piston 134 is then interrupted and the valve 222instead supplies compressed air to the space 141 from space 232 throughpassage 238, FIG. 24, annular groove 239,-

FIG. 26, space 292, groove 240, passage 241, groove 12,

FIG. 3, passage 22, port 23, passage 138, space 139, open-, ings to thepiston chamber 141. The chamber 142,

In this and the other as the operator releases the lever 224 theprevious feeding conditions and feed pressure are restored.

The invention may be modified in several different ways by those skilledin the art within the scope of the following claims.

What I claim is:

1. A rock drilling mechanism comprising a drill steel actuating motorand a feeding device for movement of said motor toward a rock face to bedrilled, a working cylinder for compressed air in said motor, passagesin the motor for conveying flushing water to a flushing medium duct insaid drill steel, passages in the motor for conveying compressed air tosaid flushing medium duct in the drill steel, passages in the motor forsupplying compressed air to said working cylinder of the motor fordriving the same, passages in the motor for conveying compressed air tosaid feeding device and for venting air from the feeding device,compressed air and flushing water connections at one longitudinal sideofthen to a position in which water is supplied to the flush-'- ingmedium duct and air is still supplied to the feeding device and then topositions in which air is supplied to the motor and the feeding deviceand water to the flushing medium duct, a pressure reduction deviceprovided with an operating member for controlling the pressure of thecompressed air supplied to the feeding device, said feeding device beingpivotally connected to the underside of said motor to allow the motor toswing on a transverse axis relative to the feeding device, and saidoperating means being positioned substantially within the cross sectioncontour of the motor and accessible from the rear and upper side of themotor leaving the underside and one longitudinal side free of operatingmeans and hose connections.

2. A rock drilling mechanism comprising a drill steel actuating motoradapted for cooperation with a pneumatic feeding device and having acasing, a working cylinder for compressed air in said casing, a membermovable in said working cylinder under the action of said compressedair, a back head on the casing, a cylindrical main control valve memberin said back head mounted to turn in a first cylindrical bore in theback head with the bore axis substantially parallel to the axis of theworking cylinder and arranged for control of the compressed air supplyto the working cylinder, a cylindrical auxiliary valve member in saidback head mounted to turn in a second cylindrical bore in the back headwith the bore axis substantially parallel to the axis of the workingcylinder and arranged for control of the compressed air pressure in saidfeeding device, levers for manipulating said valve members, and a handleon the back head extending transversely to the axis of the workingcylinder, said handle being off-set relative to said levers, and saidfeeding device being pivotally connected to the underside of said motorto allow the motor to swing on a transverse axis relative to the feedingdevice, and said operating means being positioned substantially withinthe cross section contour of the motor and accessible from the rear andupper side of the motor leaving the underside and one longitudinal sidefree of operating means and hose connections.

3. A rock drilling mechanism comprising a drill steel actuating motoradapted for cooperation with a pneumatic expansible and retractablefeeding device and having a casing, a working cylinder for compressedair in said 10 casing, a member movable in said working cylinder underthe action of said compressed air, a back head on the casing, acylindrical main control valve member in said back head mounted to turnin a first cylindrical bore in the back head with the bore axissubstantially parallel to the axis of the working cylinder and arrangedfor control of compressed air supply to the working cylinder and offlushing water or air to the drill steel and compressed air to thefeeding device, a cylindrical auxiliary valve member in said back headmounted to turn in a second cylindrical bore in the back head with thebore axis substantially parallel to the axis of the working cylinder andarranged for control of the air pressure in. said feeding device, a ventvalve member in the back head for venting air from the feeding device,and means on the back head for manipulating said valve members toproduce drilling, flushing, feeding and retraction of the drill, andsaid feeding device being pivotally connected to the underside of saidmotor to allow the motor to swing on a transverse axis relative to thefeeding device, and said operating means being positioned substantiallywithin the cross section contour of the motor and accessible from therear and upper side of the motor leaving the underside and onelongitudinal side free of operating means and hose connections.

4. A rock drilling mechanism comprising a drill steel actuating motoradapted for cooperation with an expansible and contractable pneumaticfeeding device and having a casing, a working cylinder for compressedair in said casing, a member movable in said working cylinder under theaction of said compressed air, a back head on the casing, two side boltsextending through said back head and casing for holding together theback head and casing, a cylindrical main control valve member in theback head mounted to turn in a first cylindrical bore in the back headoff-set to one side of a plane through said side bolts and having thebore axis substantially parallel With the axis of the working cylinderand arranged for controlling the compressed air supply to the workingcylinder, a cylindrical auxiliary valve member in said back head mountedto turn in a second cylindrical bore in the back head off-set to thesame side of said plane as said first bore and having the bore axissubstantially parallel to the axis of the working cylinder and arrangedfor control of the compressed air pressure in said feeding device,levers on said cylindrical valve members arranged to turn the valvemembers for manipulating said valves, a handle on the back headextending transversely to the axis of the working cylinder parallel withsaid plane and ofiF-set to the opposite side of said plane to said valvemembers, a lever pivoted in said handle, and an air vent valve in theback head arranged for venting air from the feeding device to causecontraction of the feeding device and arranged to be moved to openposition by means of said lever in the handle upon the swinging of saidpivoted lever.

5. A rock drilling mechanism according to claim 4, in which the pivotedlever in the handle is a double armed lever extending with one endthrough the rear side of the handle and with the other end through theforward side of the handle.

6. A rock drilling mechanism comprising a drill steel actuating motoradapted for cooperation With a pneumatically expansible and retractablefeed leg and having a casing provided with means for pivotal attachmentof said feed leg at the longitudinal underside of said casing forswinging of the motor on a transverse axis relative to said feed leg, aworking cylinder for compressed air in said casing, a member movable insaid working cylinder under the action of said compressed air, abackhead on the casing, a main control valve member in said backheadarranged for control of compressed air supply to the working cylinder,an auxiliary valve member in the backhead arranged for control of theair pressure in said feed leg, shiftable valve means associated withsaid backhead 11 and arranged for controlling expansion and contraction,respectively, of said feed leg and for venting the feed leg, fluid hoseconnections at one longitudinal side of the backhead, and operatingmeans at the backhead substantially within the cross section contour ofthe motor and accessible from the rear and upper side of the motorleaving the underside and one longitudinal side free of operating meansand hose connections.

7. A rock drilling mechanism comprising a drill steel actuating motorand a power expansible and power'retractable feed leg, said motor havinga casing with means for pivotal attachment of said feed leg for swingingof said motor on a transverse axis relative to said feed leg and to thelongitudinal axis of said motor, an expansion chamber in said feed leg,a retraction chamber in said feed leg, passages in said motor and saidfeed leg for conveying pressure fluid to said chambers and for ventingthe same, a backhead and handle on said casing, a spring biasedshiftable distributing valve means associated with said backhead, saidvalve means being arranged in said passages for normally admittingpressure fluid to said expansion chamber and venting said retractionchamber, and a push rod longitudinally movable relative to and carriedby said backhead for engaging said shiftable valve means upon actuationto move said valve means to a position in which pressure fluid isadmitted to the retraction chamber and vented from the expansionchamber.

8. A rock drilling mechanism according to claim 7, in which the backheadand handle has a grip portion extending transversely to the longitudinalaxis of the motor, and a supporting portion extending longitudinally ofthe motor and carrying said grip portion, said push rod being arrangedin said supporting portion, and a swingable lever mounted in said gripportion and engaging said push rod with one end for manipulatingpressure fluid into said chamber, main conduit means for supplying fluidpressure to said apparatus for operation of said drilling motor and saidfeed leg, main valve means for controlling said supply of pressurefluid, internal conduit means in said casingand said feed leg forsupplying pressure fluid from said main conduit means to bothsaidchambers in said feed leg, auxiliary valve means for controlling thepressure of said pressure fluid supplied into said chamber of said feedleg,vent means for venting pressure fluid from each of said chambers,distributing valve means in flow communication with said internalconduit means and said vent means and selectively movable from a firstposition for supplying pressure fluid to said first chamber whileventing said second chamber to a second position for venting said firstchamber while supplying pressure fluid to said second chamber, andseparate operating means for operating each of said main valve andauxiliary valve and distributing valve means, all said main conduitmeans and said operating means for each of said valve means beingdisposed on said apparatus adjacent one side only of said backhead andaccessible to said operator while grasping said manipulating meanswhereby the opposite side of said backhead is substantiallyfree of fluidconduits and valve operating means.

References Cited in the file of this patent UNITED STATES PATENTS1,175,745 Gilman Mar. 14, 1916 1,407,590 Slater Feb. 21, 1922 1,862,497Rundgvist June 7, 1932 3,064,741 Morrison Nov. 20, 1962 3,065,806Thompson Nov. 27, 1962

1. A ROCK DRILLING MECHANISM COMPRISING A DRILL STEEL ACTUATING MOTORAND A FEEDING DEVICE FOR MOVEMENT OF SAID MOTOR TOWARD A ROCK FACE TO BEDRILLED, A WORKING CYLINDER FOR COMPRESSED AIR IN SAID MOTOR, PASSAGESIN THE MOTOR FOR CONVEYING FLUSHING WATER TO A FLUSHING MEDIUM DUCT INSAID DRILL STEEL, PASSAGES IN THE MOTOR FOR CONVEYING COMPRESSED AIR TOSAID FLUSHING MEDIUM DUCT IN THE DRILL STEEL, PASSAGES IN THE MOTOR FORSUPPLYING COMPRESSED AIR TO SAID WORKING CYLINDER OF THE MOTOR FORDRIVING THE SAME, PASSAGES IN THE MOTOR FOR CONVEYING COMPRESSED AIR TOSAID FEEDING DEVICE AND FOR VENTING AIR FROM THE FEEDING DEVICE,COMPRESSED AIR AND FLUSHING WATER CONNECTIONS AT ONE LONGITUDINAL SIDEOF SAID MOTOR, MEANS IN THE MOTOR FOR CONTROLLING THE FLUSHING WATERPASSAGES, A MAIN VALVE IN SAID MOTOR ARRANGED FOR CONTROL OF SAIDFLUSHING WATER CONTROLLING MEANS AND SAID COMPRESSED AIR PASSAGES ANDCOMPRISING A CYLINDRICAL MAIN VALVE MEMBER MOUNTED TO TURN IN THE MOTORIN A CYLINDRICAL BORE WITH THE BORE AXIS SUBSTANTIALLY PARALLEL TO THEAXIS OF THE WORKING CYLINDER, AN OPERATING LEVER FOR TURNING SAID MAINVALVE MEMBER FROM A POSITION IN WHICH AIR IS SUPPLIED TO THE FLUSHINGMEDIUM DUCT TO A POSITION IN WHICH AIR IS SUPPLIED TO THE FEEDING DEVICETHEN TO A POSITION IN WHICH WATER IS SUPPLIED TO THE FLUSHING MEDIUMDUCT AND AIR IS STILL SUPPLIED TO THE FEEDING DEVICE AND THEN TOPOSITIONS IN WHICH AIR IS SUPPLIED TO THE MOTOR AND THE FEEDING DEVICEAND WATER TO THE FLUSHING MEDIUM DUCT, A PRESSURE REDUCTION DEVICEPROVIDED WITH AN OPERATING MEMBER FOR CONTROLLING THE PRESSURE OF THECOMPRESSED AIR SUPPLIED TO THE FEEDING DE-